The present invention is directed to an auxiliary driving device for transporting of sheets of paper or cardboard, specifically for the transport of sheets of paper or cardboard that are arranged tilewise or in a shingled stream from a feeding station of a die-cutting press to the die-cutting station of such a press.
In the die-cutting presses known up to now, the sheets to be processed are seized from the top of a pile located in the feeding station and delivered tilewise or in a shingled stream onto a feeding table before being introduced into the grippers of the transporting elements of the die-cutting station of the press. The sheets are obviously accurately aligned longitudinally and laterally before being seized by the grippers of the transporting element of the die-cutting press. This alignment occurs at one end of the feeding table and is achieved by front lays or stops and side marks or stops onto which the sheet that is to be introduced into the die-cutting station of the press is to be applied. The current feeding tables generally include a slanted plate which serves as a support for the upper runs of sheet transporting belts arranged side-by-side across the width of the slanted plate. In order to insure the transport of the sheet from the stream onto the feeding table, auxiliary upper pressure means are provided which are fitted on a frame so as to be set in position above the upper run of every sheet transporting belt. These auxiliary pressure means consist of a small belt carrier whose pressure on the stream of sheets to be transported can be adjusted. In order to insure, without damage, the application of a front edge of the first sheet of the stream on the front lays, a preferred embodiment makes use of a rotary brush whose rotation axle is offset longitudinally with regard to the end pulley of the belt carrier. Thus, the rear edge of the first sheet of the stream will not be pushed in the travelling direction by the carrier belt, but only the bristles of the rotating brush, which bristles will give way when the front edge of the first sheet of the stream comes into contact with the front lays. Thus, the sheet will not be deformed or damaged by too strong of a pushing force by the transporting elements.
In this kind of device, it is obviously appropriate to drive the rotary brush. To this aim, the motion of one of the end pulleys of the first carrier is used and transmitted to the brush by means of a driving belt.
These auxiliary pressure means, thus, have several drawbacks. First of all, their construction does not permit the setting of the rotary torque of the brush because of its drive by means of a belt which must necessarily be tight to be efficient. Moreover, these elements require the use of a large number of components, such as pulleys, belts and at least two pressure setting devices, which fact makes their realization particularly expensive. In addition, due to their complexity, the setting for obtaining an adequate transport of the stream of sheets is long and fastidious.